Compositions for engine operation



Nov. 17, 1959 Filed Sept. 13, 1957 J. E. BROWN COMPOSITIONS FOR ENGINEOPERATION FIGURE l 2 Sheets-Sheet 1 INVENTOR. JEVOME'EBROWN Nov. 17,1959 J. BROWN 2,913,413

COMPOSITIONS FOR ENGINE OPERATION Filed Sept. 13, 1957 2 Sheets-Sheet 2FIGURE 2 n: u..| tn 2 :3 z

L|.l 2 S u o w 2 7: u m o z T K L Y IOO Pb 50 Pb O Pb 0 Mn 50 Mn I00 MnWEIGHT PER CENT OF TOTAL METAL INVENTOR JEROMEE BROWN an internalcombustion engine.

United States COMPOSITIONS FOR ENGINE OPERATION Jerome E. Brown,Detroit, Mich., assignor to Ethyl Corporation, New York, N.Y., acorporation of Delaware This invention relates to a method of operatinga spark ignition internal combustion engine which utilizes novelcompositions of-matter containing a non-ionic metal polycarbonylcompound which enable an engine to give knock-free performance and whichpossess numerous benefits in connection with improved combustioncharacteristics and the alleviation of modern day engine problems. Thisapplication is a continuation-in-part of prior applications Serial No.365,279, filed June 30, 1953 (now abandoned.) and Serial No. 446,181filed July 27, 1954 (now abandoned), which in turn werecontinuations-inpart of prior application Serial No. 234,463, filed June29, 1951 (now abandoned).

In the drawings accompanying this specification:

Figure 1 is a schematic representation of an embodiment of thisinvention and Figure 2 is a graphic representation of the beneficialeffect obtained from the use of certain of the compositions of thisinvention.

Concurrent with the development of'the modern high eificiency, highcompression ratio, internal combustion engine of the spark ignitiontype, it was necessary to develop fuels which would permit theknock-free operation required to utilize most effectively these advancesin engine design. The approach to this problem has been in .twodirections. On the one hand, improvements in refining operations havebeen undertaken to provide hydrocarbon fuels wherein the ingredients ormixtures thereof possess high antiknock quality. There exists, however,a limit, depending on a number of factors, beyond which the fuels cannotbe economically improved. On the other hand, additives have beenprovided for such fuels whereby a further increase in the antiknockquality of the mixture is produced.

atent The most successful antiknock additive from a practical standpointhas been tetraethyllead. From time to time, a number of other antiknockmaterials have been proposed, but none of them have attained commercialSignificance in this country.

It is an object of this invention to provide an improved method foroperating an internal combustion engine. Another object is to providenew compositions of matter. A more specific 'object is to provide newgasoline compositions. It is also an object of this invention to providea gasoline containing metal polycarbonyl antiknock compounds or mixturesof such compounds which possess greatly reduced wear causingcharacteristics. A still further object is to provide gasoline suitablefor use in high efficiency, spark ignition internal combustion enginesrequiring a fuel of high antiknock quality. Still another object is toprovide a lubricating oil which acts to reduce the octane requirement ofAmong the other objects of this invention is the alleviation of engineproblems including octane requirement increase, spark plug fouling andsurface ignition. Additional objects of the instant invention will beapparent from the discussion which follows:

The above and other objects of this invention are acice complished byproviding a process for operating a spark ignition internal combustionengine which comprises introducing into the cylinders thereof, anon-ionicmanganese polycarbonyl antiknock agent. The objects of thisinvention are also accomplished by providing, ,as novel compositions ofmatter, gasoline, lubricating oil and antiknock fluids containing anon-ionic manganese polycarbonyl compound or mixtures of manganesepolycarbonyl compounds as antiknock agents.

Thus among the important compositions contemplated by the presentinvention are included a hydrocarbon fuel of the gasoline boiling rangefor use in spark ignition internal combustion engines containing a smallamount of manganese pentacarbonyl .sufficient to improve the antiknockproperties of said hydrocarbon fuel. For most purposes this amount ofmanganese pentacarbonyl will range from about 0.01 gram to about 6 gramsof manganese per gallon of fuel. In a preferred embodiment of theinvention the amount of manganese pentacarbonyl is regulated so as to befrom 0.2 gram to 4 grams of manganese per gallon. More specifically, thepresent invention contemplates a hydrocarbon of the gasoline boilingrange for use in spark ignition internal combustion engines containingsubstantially 1.77 grams of m'anganese'in the form of manganesepentacarbonyl per gallon of fuel. The present invention also embracesthe process of obtaining improved operating characteristics of a sparkignition internal combustion engine which comprises operating saidengine on a fuel composition which consists of a hydrocarbon fuel of thegasoline boiling range containing a small amount of manganesepentacarbonyl suflicient to improve the antiknock properties of saidhydrocarbon fuel.

It is essential that the manganese polycarbony-l compounds used in thepractice of this invention be nonionic in nature in order that theyproduce the desired effect. For example, ionic manganese carbonylcompounds such as those having halogen bonded directly to manganese arenot sufiiciently volatile to be readily inductible into the cylinders ofa multi-cylinder engine using a manifold type intake valve. Thesecompounds are unable to give the benefits attributable to non-ionicmanganese polycarbonyl compounds.

An unexpected feature of this invention is that the non-ionic manganesepolycarbonyls are among the most effective antiknock agents tested todate. This is particularly surprising when it is considered thatmanganese is located in the Periodic Table next to the element chromium.Chromium carbonyl exhibits a pro-knock effect when employed as agasoline additive for use in a spark ignition internalcombustion'engine.

Even when 'a compound has exceptional antiknock activity, the chances ofits becoming a useful product remain extremely remote. This is due tothe fact that many other properties must be taken into considerationbefore a new product can be seriously considered as a useful product.Thus, in the past, compounds having antiknock activity have beenrejected from the commercialization because they (a) Have a deleteriouseffect on the operation of an engine (b) Are not sufficiently soluble inthe fuel (0) Are not volatile enough for proper engine inductibility (d)Possess objectionable odors (e) Bring about excessive wear.

For example, various iron and nickel compounds including iron carbonyland dicyclopentadienyl nickel have been suggested as antiknocks but havenot been accepted due to the excessive engine wear caused by their use.As a further example, many aromatic amines exhibit quired of commercialadditives.

antiknock acitivity, but their use is not feasible due to the fact thatthey exude a particularly objectionable odor.

Therefore, to be commercially successful, an antiknock must possess manyauxiliary properties in addition to outstanding antiknock activity. Anycompound under consideration must undergo extensive tests to insure thatit meets the important secondary qualifications.

It has been found that the non-ionic manganese polycarbonyl compounds,which are the subject of the present invention, possess all therequirements of a successful antiknock to a remarkable degree. That is,they not only exhibit outstanding antiknock effectiveness, but inaddition have the properties (including volatility, stability, gasolinesolubility, lack of gum forming tendencies, minimization of enginedeposits and engine wear and susceptibility to preparation fromavailable materials) re- For example, manganese carbonyl causes onlyabout one-fifth the wear caused by an equivalent amount of iron as ironcarbonyl.

The fuels and lubricants used in todays high compression automotiveengines cause deposits to be formed during combustion. These depositswhich are derived from the fuels and lubricating oils and the additivestherein collect on essentially all parts of the combustion chamberincluding the valves, the spark plugs and the cylinder Walls. Theformation of these deposits leads to several problems such as octanerequirement increase, deposit induced ignition and spark plug fouling.These problems prevent maximum utilization of the potential of a fueland limit the designer from providing engines which will accomplish thisend.

Not only do the non-ionic manganese polycarbonyl compounds exhibit theproperties required of a successful antiknock, but they also havevaluable and unexpected auxiliary effects on the operation of a sparkignition internal combustion engine. It has been found that thesecompounds minimize octane requirement increase and deposit inducedignition and increase the spark plug life of the modern high compressionspark ignition internal combustion engine.

An important embodiment of this invention is gasoline containing, inamounts sufficient to improve the octane quality thereof, a non-ionicmanganese polycarbonyl compound which is soluble in the gasoline. It hasbeen found that non-ionic manganese polycarbonyl compounds are ofoutstanding effect as antiknock agents. The amount of the manganesepolycarbonyl compound present in the compositions of this invention isregulated such that at least about 0.01 gram of manganese is present pergallon of the finished gasoline, and ordinarily up to about 6 grams ofmanganese per gallon is provided. In a preferred embodiment the amountof manganese polycarbonyl is regulated to provide from 0.2 gram to 4.0grams of manganese per gallon of fuel.

The upper limit of beneficial use of the non-ionic manganesepolycarbonyl compounds is, as a practical matter, limited due to thefact that at high concentrations the magnitude of the octane numberbenefit obtainable per unit weight of compound decreases to some extent.Thus, the most beneficial antiknock effect of the non- 'ionic manganesepolycarbonyl compound is realized when these compounds are employed inconcentrations 'such that there is from about 0.03 to about 10 grams ofmanganese per gallon of the finished gasoline. At higher concentrationsthe antiknock efiect per unit weight is diminished, and the otherbeneficial efiects are also reduced. When used as a primary additive,the best results are obtained when from about 0.01 to about 6 grams ofmanganese are present in the gasoline.

Spectacular results are obtained in the alleviation of CR1 (the octanerequirement increase due to engine deposits) and surface ignition by theuse of the manganese polycarbonyls. These deposit modifying effects areobtained both in the presence and absence of organolead antiknockagents. Drastic increases in spark plug life are also imparted by thesecompositions, particularly when the gasoline also contains at least0.015 percent of sulfur. The sulfur can be either naturally-occurringsulfur or added sulfur in the form of gasoline-soluble organiccompounds. In either case this sulfur is typically in the form ofelemental sulfur, hydrogen sulfide, mcrcaptans, sulfides, thiophenes,disulfides, polysulfides and the like. The benefits of this inventionare realized in either event.

An outstanding feature of the present invention which is of the greatestcommercial importance is the unexpected discovery that the non-ionicmanganese polycarbonyl compounds exhibit two distinct types ofsynergistic effects when used in conjunction with organolead antiknockagents. One of these eifects occurs at manganese concentrations of aslow as 0.5 percent of the lead present in the fuel and consists of anincrease in octane quality of the fuel of a completely unpredictablemagnitude. The other synergistic eifect is achieved at higher manganeseproportions and consists in realization of an octane quality much abovethat to be expected on the basis of determination with either componentalone.

When small amounts of manganese as a non-ionic manganese polycarbonylcompound are used in con junction with from 1 to about 6 grams of leadper gallon as an organolead compound, a synergistic effect is obtainedin terms of the increase in octane quality of the gasoline. This effectis realized at manganese concentrations up to about 15 percent of thetotal metal concentration of the fuel, and is observed at concentrationsas low as 0.03 gram of manganese per gallon in fuels containing at least1 gram of lead as an organolead-compound, such as tetraethyllead, pergallon.

The increase in octane number obtained by replacing a small amount oflead with an equal amount of manganese as a non-ionic manganesepolycarbonyl compound is totally unexpected. That is, a great percentageof the increase which is obtainable from a complete replacement of leadwith a non-ionic manganese polycarbonyl is realized with the firstincremental amounts of the latter. Thus, a mixture of 95 percent leadand 5 percent manganese as a non-ionic manganese polycarbonyl compoundaffects as much as 50 percent of the improvement in octane quality whichcan be realized with a complete replacement of lead with such acompound.

This phenomenon can be more readily appreciated by reference to Figure 2which is a graphical representation of the change which occurs in theantiknock quality of a fuel having 3 grams of metal per gallon in theform of a pure organolead compound, a pure manganese polycarbonylcompound or appropriate mixtures of these. The ordinate expresses theoctane quality of the gasoline in terms of octane number while theabscissa indicates the mixture of antiknoclr agents which produces thisoctane number. If the gasoline having 3 grams of lead as tetraethylleadhas the octane number indicated by point I of Figure 2 and a higheroctane number as shown on point I of the figure when it contains 3 gramsof manganese as a non-ionic manganese polycarbonyl, it would be expectedthat any intermediate compositions comprising a mixture of organoleadand non-ionic manganese polycarbonyl antiknock agents would give aresulting fuel having the octane quality rating indicated by the dashline II. However, as illustrated by the point K in Figure 2, addition ofa minute quantity of a non-ionic manganese polycarbonyl compound to theleaded fuel gives the fuel an octane rating sharply above the predictedvalue. The actual octane number enhancement achieved by addition of aminute amount of non-ionic manganese polycarbonyl to a leaded fuelranges up to several hundred percent of the predicted value.

In general the outstanding synergistic results are realized withcompositions whose antiknock constituent contains between about 5 and 10percent manganese and to 95, percent lead when th total metalconcentration is 1 gram per gallon. At the higher total metalconcentrations the synergism is evidenced by a somewhat wider range ofcompositions. Thus, when the total metal concentration is 2 grams pergallon the synergism is realized by utilizing compositions which containfrom 2 to about 13 percent of manganese, the balance being lead. Whenthe total metal concentration is about 3 grams per gallon thesynergistic effect is realized with from about 1 to about 15 percentmanganese. At still higher concentrations the synergism is realized whenthe proportions of manganese in the antiknock agent is as low as 0.5percent.

The magnitude of the above described effect varies somewhat dependingupon the nature of the gasoline. However, in general the mostsignificant advance in octane number with increased manganeseconcentrations is in the range between 2 and percent manganese based onthe amount of Pb present. These concentrations are found to give aboutone-half the effect realized from the conversion from lead to anon-ionic manganese polycarbonyl. Thus, when a small amount (from about2 to about 10 percent) of a non-ionic manganese polycarbonyl compound isused in conjunction with an organolead antiknock agent, a verysignificant increase in octane quality is obtained which would not bepredicted by a comparison of the relative eifect obtainable from anorganolead antiknock and a non-ionic manganese polycarbonyl compound.

Even at higher concentrations a manganese polycarbonyl compound inadmixture with an organolead compound produces an increase in the octanerating of a gasoline which cannot be accounted for by virtue of theorganolead compound and the manganese polycarbonyl compound additively.This elfect is observed when at least 1 gram of manganese as a non-ionicmanganese polycarbonyl is employed. Thus, an embodiment of thisinvention is an improved gasoline containing a synergistic mixture of atleast 1 gram per gallon of manganese as a manganese polycarbonylcompound in admixture with an organolead compound. Generally, the amountof such organolead compound is sufiicient to give a lead concentrationof from about 0.5 to about 8 grams per gallon.

Such a synergism is illustrated by a mixture of manganese carbonyl andtetraethyllead. When tested alone in a commercial gasoline, manganesecarbonyl is found to be 1.9 times as effective as tetraethyllead on aWeight of metal basis. Thus, a fuel containing 1 gram of manganese asmanganese carbonyl and 1 gram of lead as tetraethyllead would beexpected to give the same octane number as a fuel containing 2.9 gramsof lead as tetraethyllead. However, such a mixture gave an octane numberincrease which would only be realized with the addition of 3.8 grams oflead. Therefore, the addition of 1 gram of manganese as manganesecarbonyl gave about twice its expected effect.

It has also been found that when a manganese polycarbonyl compound isadded to the crankcase lubricating oil of an internal combustion engine,a drastic and rapid decrease in the octane requirement of the enginetakes place. This is believed to be due to the fact that the manganesepolycarbonyl compound enters the cylinders of the engine either as avapor or in the oil film on the cylinder walls. Thus, the objects ofthis invention are also accomplished by providing a lubricating oil forinternal combustion engines, which oil contains a manganese polycarbonylcompound in amount suflicient to reduce the octane requirement of thefuel used in the engine.

As the non-ionic manganese polycarbonyl compounds find outstanding andunexpected utility as additivesto both gasoline and crankcaselubricating oil, this invention gives rise to novel compositions ofmatter comprising a liquid hydrocarbon mixture useful in a sparkignition internal combustion engine, which mixture contains a non-ionicmanganese polycarbonyl compound in amount sufiicient to improve thecombustion characteristics of the engine.

The non-ionic manganese polycarbonyl antiknock agents of this inventionare also conveniently introduced into the cylinders of an internalcombustion engine by utilizing a separate system of supply inconjunction with the system which supplies fuel to the cylinders. Thus,the non-ionic manganese polycarbonyl compounds are supplied to thecylinders by atomiz ing, vaporizing or directly spraying the compound ora solution thereof, directly into the cylinders or into the intakemanifold which supplies the cylinders with fuel. Introduction of thenon-ionic manganese polycarbonyl compound into the manifolding systemmay be accomplished either prior or subsequent to carburetion orinjection of the gasoline. When the non-ionic manganese polycarbonylcompound is a solid, it is often possible to vaporize it by passing astream of air over or through a supply of the compound. When thecompound is a liquid, it is conveniently supplied to the intake manifoldthrough a wick which is supplied from a reservoir of the liquid.

Figure 1 is illustrative of a method of introducing a non-ionicmanganese polycarbonyl compound into a combustion chamber of an internalcombustion engine having a plurality of combustion chambers equippedwith movable pistons wherein the walls of the chambers are lubricatedwith a crankcase lubricating oil and wherein gasow line is introducedinto the combustion chamber and ig-' nited and the products ofcombustion act upon the pistons and produce a driving force. Withreference to Figure 1, the numeral 10 generally represents a cylinderand cylinder head of a multi-cylinder spark ignition internal combustionengine which contains a piston 11, combustion chamber 12, spark plug 13which is under the influence of an ignition system (not shown), intakevalve 14 and intake port 15 through which gasoline and combustion airare supplied by a carburetion system (not shown), an exhaust valve 16and an exhaust port 17. These components make up the basic partsrequired in a conventional four-cycle spark ignition internal combustion engine. I

To eflectively conduct the process ofthis invention, a non-ionicmanganese polycarbonyl compound is conveniently injected into thecombustion chamber 12 by the utilization of a separate injection systemwhich consists of a supplemental opening 18 which has fitted theretoavalve 19 shown for purposes of illustration as a poppet valve heldclosed by a spring 20 and having an elongated stem 21 which places thevalve under the influence of a solenoid 22. The solenoid 22 isconveniently arranged to be under the influenceof a set of breakerpoints (not shown) coordinated with the ignition system of the engine sothat the valve 19 will be open during the intake stroke of the piston 11for a time sufi'icient to permit the required amount of non-ionicmanganese polycarbonyl compound to enter the combustion chamber 12. Thenon-ionic manganese polycarbonyl compound is supplied through theopening 18 by means of avaporizing system 23 which terminates in aninlet port 24 through which the valve stem 21 operates by means of theaperture 25. The valve stem 21 is sealed in the aperture 25 in anyconvenient manner. To supply a non-ionic manganese polycarbonyl compoundas a vapor to the combustion chamber 12 through the opening 18, areservoir 26 of any convenient form contains a supply of manganesepolycarbonyl compound to a convenient level 27. The container 26 isfitted with a means for passing vaporizing gas through the manganesepolycarbonyl compound as shown by the conduit 28 which is attached to anopening 29 in the container 26. Back-up in the conduit 28 is preventedby any convenient means, such as a diaphragm valve 30. To the upperportion of the container 26 is attached a'plurality of conduits 31corresponding to the number of cylinders in the engine. The conduits 31terminate in the inlet port 24. p A vaporizing gas, such as nitrogen,air, carbon dioxide and the like, supplied from any convenient meanssuch as a compressor or tank (not shown) through the conduit 2'81pa'ssesthrough the manganese polycarbonyl compound 27 and carries the compoundas a vapor through the conduit 31 to the inlet port 24 where at theappropriate time it passes through the aperture 18 into the combustionchamber 12 where it mixes with the gasoline and combustion air andimproves the combustion which takes place under the influence of sparkplug 13 at the end of the compression stroke of the piston 11. Themanganese polycarbonyl compound shown at 27 may be in the form of asolid such as methyl manganese pentacarbonyl or may be a liquid whichcontains a non-ionic manganese polycarbonyl which may be blended with anantiknock fluid containing halogen scavenger material and an organoleadantiknock agent such as tetraethyllead.

Fuels containing organolead antiknock agents ordinarily contain, inaddition to the antiknock agent, corrective agents commonly termedscavengers. Thus, when organolead antiknock agents are present in thecompositions of this invention, it is desirable to include therewithsuch scavengers. These scavengers consist of organo bromine and/orchlorine compounds such as ethylene dibromide, ethylene dichloride andlike material. They function to inhibit the build-up of lead deposits onthe interior surface of internal combustion engines.

Halogen containing hydrocarbons are useful as scavengers in conjunctionwith the manganese polycarbonyl antiknock agents and are convenientlyblended therewith to form fluids which are added to gasoline to give thebenefits of this invention. These fluids also may contain small amountsof such hydrocarbon solvents as kerosene as well as dyes, antioxidantsand the like. The proportion of halogen in such compositions is adjustedsuch that an atom ratio of halogen to manganese of from about 0.221 upto 12:1 is achieved. However, the octane enhancement of the manganesepolycarbonyl compounds is realized even in the absence of suchscavengers.

Organolead antiknock agents are commonly provided as fluids for additionto hydrocarbon fuels. These fluids ordinarily contain the organoleadcompound and the halogen scavenger agents referred to above. Inaddition, these fluids also often contain solvents comprising mixturesof hydrocarbons as well as antioxidants and the like. Thus, anothervariant within the purview of this invention is the provision of anantiknock fluid comprising an organolead compound and a manganesepolycarbonyl compound. These fluids are conveniently blended withhydrocarbon fuels to prepare the improved fuels of this invention.

Because of the property inherent in the manganese polycarbonyl compoundswithin the scope of this invention of being highly soluble in gasoline,such blending operations present little or no difficulties. It isgenerally necessary only to add the requisite quantity of an improvedantiknock fluid of the present invention to gasoline; and, by stirring,shaking or otherwise mechanically agitating'these components,homogeneous improved fuel compositions are obtained. As a result of thehigh solubility of the'antiknock fluids of this invention in gasolinesuch fluids can be utilized in any commercially available gasolineincluding straight run, catalytically cracked, catalytically reformedand thermally cracked base stocks and likewise, blends thereof.

Among the manganese carbonyl compounds suitable for use in the presentinvention are those which have the empirical formula R Mn(CO) where R isan organic radical, x ranges from to '7 and y is an integer from 2 to 5.However, the non-ionic manganese polycarbonyl compounds preferred in thepractice of this invention are those where R is a monovalent organicradical, x ranges from 0 to l inclusive, such that when x is 0, y is andwhen x is l, y is a small odd integer from 3 to 5 inclusive. R is mostpreferably a monovalent aliphatic hydrocarbon radical, such as an alkylor aryl radical, or a monovalent acyl radical. Examples of thesecompounds include manganese carbonyl, methyl manganese pentacarbonyl,benzoyl manganese pentacarbonyl, phenyl manganese pentacarbonyl, acetylmanganese pentacarbonyl, and the like. These and other manganesepolycarbonyl compounds exhibit extraordinary antiknock effect and otherunexpected properties which render them of interest as commercialantiknock agents.

The relative size of the organic radical in the manganese carbonylcompounds, while not too important, is best limited to those having from1 to about 20 carbon atoms, as it is found that these are best suited tothe practice of this invention. Compounds having organic groupscontaining from 1 to 13 carbon atoms are preferred as these compoundsare found to best combine the qualities of volatility and inductibilitywhich are prerequisites to proper functioning as gasoline additives.

When x in the above generic formula is 0, the formula becomes Mn(CO)This compound exists, under some conditions, as the dimer having theformula [Mn(CO) 1 and is prepared, for example, by a process which manprises the reduction of a manganese halide with a reducing agent such asmagnesium in the presence of a catalyst under pressure of carbonmonoxide at elevated temperatures. Manganese carbonyl is recovered fromthe reaction mixture by acid hydrolysis followed by steam distillation.

Manganese carbonyl is a solid at ordinary temperatures, having a meltingpoint when pure of about 155 C., and a density of about 1.2. Thematerial possesses a vapor pressure of 1 millimeter of at C. Manganesecarbonyl is stable in the ordinary sense of the term up to a temperatureof about 200 C. It is soluble in gasoline, but is insoluble in water andaqueous solutions.

Compounds having the formula RMn(CO) where the R represents an organicradical from the group consisting of organic hydrocarbon radicals andorganic oxygen containing radicals, are conveniently prepared frommanganese carbonyl in an ether solution. Manganese carbonyl is firstconverted to an alkali metal salt such as the sodium salt by treatingthe solution with an alkali metal present by an alkali metal dispersionor amalgam. The alkali metal salt is then reacted with an alkylatingagent such as a dialkyl sulphate to form an alkyl manganesepentacarbonyl. Alternatively, the alkali metal salt of manganesecarbonyl is reacted with an acyl halide to form an acyl manganesepentacarbonyl compound. These acyl manganese pentacarbonyl compounds areconverted to the corresponding lower alkyl or aryl manganesepentacarbonyl compounds by pyrolysis accompanied by the loss of CO atelevated temperatures. Thus, phenyl manganese pentacarbonyl isconveniently produced by the pyrolysis of benzoyl manganesepentacarbonyl.

The lowest molecular weight compound having the formula RMn(CO) ismethyl manganese pentacarbonyl which is a crystalline solid melting atabout C. and which is highly volatile and soluble in gasoline. Anothercompound of this class is benzoyl manganese pentacarbonyl, also asoluble crystalline solid, which melts at about 38 C. Propyl manganesepentacarbonyl and acetyl manganese pentacarbonyl are otherrepresentative members.

In order to illustrate the utility and some of the commercial advantagesof employing the manganese carbonyl compounds used in the practice ofthis invention, a great number of tests have been conducted. The resultsof some of the most significant are presented below.

Another unexpected advantage which the manganese polycarbonyl compoundspossess is their extremely low wear causing characteristics. Todemonstrate the low wear rate caused by the use of manganesepolycarbonyl compounds as compared to the Wear caused when ironcontaining compounds are employed for the same purpose, the followingtests were conducted: Gasoline, con

taining manganese carbonyl on the one hand and iron carbonyl on theother, was employed in a single-cylinder engine having a displacement of35' cubic inches operating at a speed of 1850 r.p.m. at a jackettemperature of 180 F. The intake air was filtered in order to preventdust in the atmosphere from entering the combustion chamber. The amountof wear was determined according to the method disclosed in US. Patent2,315,845. It is reported in Table I below as the rate of loss in weightof the upper piston ring during the test period, in terms of milligramsper hour. The piston ring in question was made of standard cast iron andcontained radioactive isotopes. As the surface of this ring wassubjected to .wear in the operation of the engine on a particulargasoline, the wear debris was carried into the lubricating oil where itsconcentration was measured by determining the radioactivity of the oilsolution by means of a counting device. The radioactivity count was thencompared with the count obtained from a standard solution of metalsecured from the surface of a piston ring similar to the one used in thetest. By appropriate mathematical calculations, the observed count ofradioactivity of the oil was transformed to figures representing theloss in weight of the piston ring due to wear in the operating of theengine.

It is seen from Table I that at a concentration of the carbonyl compoundequivalent to 0.21 gram of the metal per gallon of fuel, manganesecarbonyl produces only 24 percent of the wear observed when ironcarbonyl is used as the additive. It is further seen that when theconcentration of the additive is increased to that equivalent to 0.62gram of the metal per gallon of fuel, the amount of wear due to the useof manganese carbonyl is only 15.5 percent of that observed when ironcarbonyl is the additive. Stating this in a different manner, ironcarbonyl has been shown, as indicated in the above table, to producefrom 416 percent to 645 percent as much wear as manganese carbonylproduced in the combustion chamber of the spark fired internalcombustion engine when used as an antiknook additive in fuel. Thisfurther illustrates the desirability of employing a manganesepolycarbonyl as an antiknock agent.

TABLE I Comparison of top piston ring wear in a single cylinder testengine Additive Sulfur cone. in content, Fuel/air Duration Wear Additiveg. of Weight ratio of test, rate,

metal} Percent hours mgJhr.

gal.

PART I Fe(CO)s 0.21 0.080 23 0.646 Fe(CO)5- 0.21 0.065 19. 5 0.770Fe(GO) 0.21 0.15 0.080 20 0.86 Fe(O 0. 21 0. 15 0. 080 23 1. 02

PART II M]1(C0)n 0.21 0. 065 18 0.241 Mn(0 0);; 0.21 0. 065 20. 25 0.155

PART III Fe(C O)s 0.62 0. 080 22. 5 2. 36 Fe(OO)t 0. 62 0. 080 20 4. 52

PART IV Mn(O 0) 0.62 0.065 15 0.635

1 Average.

The unexpected nature of this drastic reduction in wear brought about bythe use of a manganese polycarbonyl compound appears at once from aconsideration of the relative hardness of the products of combustion ofthese compounds and iron antiknocks. The iron compounds produce oxideshaving relative hardness of aboutthe same magnitude as oxides producedby the manganese polycarbonyl compounds. Therefore, the great differencein wear cannot be accounted for in terms of the hardness of the productsof combustion, but rather it would be expected that they cause wear ofabout the same magnitude.

A most important feature of the present invention is the outstandingantiknock activity exhibited by the nonionic manganese polycarbonylcompounds. For example, the octane rating of typical test gasolines towhich had been added in varying proportions a manganese polycarbonyl, aswell as other previously known metal carbonyl compounds andtetraethyllead was determined by the Research Method. The ResearchMethod of determining the octane number of a fuel is generally acceptedas a method of test which gives a good indication of fuel behavior infull-scale, automotive engines under normal driving conditions and themethod most used by commercial installations in determining the value ofa gasoline or additive. The Research Method of testing antiknocks isconducted in a single-cylinder engine especially designed for thispurpose and referred to as the CFR engine. This engine has a variablecompression ratio and during the test the temperature of the jacketwater is maintained at 212 F. and the inlet air temperature iscontrolled at F. The engine is operated at a speed of 600 rpm. with aspark advance of 13 before top dead center. The test method employed ismore fully described in test procedure D-908 55 contained in the 1956edition of ASTM Manual of Engine Test Methods for Rating Fuels.

The results of these tests are summarized in Table II. In brief, theydemonstrate that the manganese polycarbonyl compounds are unexpectedlysuperior to previously used metal carbonyl antiknock agents such. asiron carbonyl. The tests also show that the non-ionic manganesepolycarbonyl compounds are vastly more effective than the presentcommercial anti'knook agent, tetraethyllead as is indicated by the factthat 1.77 grams of manganese as manganese carbonyl is as eifectiye as3.3 grams of lead as tetraethyllead.

The tests shown in Table H were conducted .in two different testgasolines, one having a research octane number rating of 60 withoutadditives (designated as A), the other having a rating of 70 octanenumbers (designated as B).

In addition to the remarkable antiknock activity of the manganesepolycarbonyl compounds, the tests shown in Table II point out theunexpectedness of this property. Tungsten and chromium are both closelyneighboring elements to manganese in the periodic classification but asthe tests show, the carbonyls of these elements both exhibit strongpro-knock activity. Similar tests were also conducted using a rheniumcontaining carbonyl compound as an additive. The results of these testsshowed the compound to have absolutely no antiknock elfect on thegasoline.

The antiknock properties of manganese polycarbonyl compounds are evenmore unexpected when it is considered that some other compounds ofmanganese are inefiective. For example, manganese naphthenate exhibits aslight pro-knock quality.

In a series of tests conducted with a multi-cylinder engine having a11.3:1 compression ratio, small amounts of manganese polycarbonylcompounds were added to the gasoline which contained 3 milliliters oftetraethyllead per gallon and the octane number of the resultinggasoline was determined by the borderline rating method to show thesynergism existing between a lead anti-knock agent and a small amount ofmanganese. When 0.062 gram of manganese per gallon as manganese carbonylwas added to the gasoline, an increase in octane quality was obtainedwhich is the equivalent of that obtained with 3.60 milliliters oftetraethyllead. Thus, the 0.062 gram of manganese gave about 950 percentof the effect obtainable with the same amount of lead.

In order to demonstrate the synergistic effect produced by utilizing alarger amount of a manganese polycarbonyl compound in combination withan organolead antiknock agent, a number of similar engine tests wereconducted utilizing the same fuel base stock to which had been addedvarious concentrations of a typical non-ionic manganese polycarbonylmaterial, manganese carbonyl. By so doing, it was found that aconcentration of this material equivalent to 1.0 gram of manganese pergallon resulted in an antiknock quality equivalent to that produced by1.9 grams of lead per gallon as tetraethylleacl. Similarly, when 1.5grams of manganese per gallon was present as manganese carbonyl, theoctane quality was found equivalent to that produced by the addition of3.8 grams of lead per gallon as tetraethyllead. The tests were conductedaccording to the Research Method referred to above. Thus, one gram ofmanganese as manganese carbonyl was the equivalent of 2.8 grams of leadwhen used in conjunction with one gram of lead instead of the 1.9 gramsof additional benefit which was expected from the manganese. Therefore,the mixture of tetraethyllead and manganese carbonyl exhibited asynergism equal to an additional 0.9 gram of lead for each gram ofmanganese. Thus, the unexpected improvement in the octane quality of agasoline was of the order of 152 percent. Similar results, as indicatedby Table III, were obtained when 1.5 grams of manganese as manganesecarbonyl were used in conjunction with one gram of lead astetraethyllead per gallon of the same gasoline. In this case, theexpected effect would be equivalent to a total of 3.85 grams of lead astetraethyllead. However, the total eliect produced by 1.5 grams. ofmanganese as manganese carbonyl and one gram of lead as tetraethylleadwas equivalent to that produced by 6.4 grams of lead alone. Thus, themixture exhibited a synergism of 190 percent over and above the effectexpected from the manganese alone.

TABLE III Metal Content Antiknoek Eileetiveness Percent Improvement Mn,Pb, Expected Obtained gJgal. gJgal.

pyllead, and the like.

12 are summarized in Table IV from which it can be seen thatthe additionof a relatively small quantity of an organo manganese pentacarbonyl,such as methyl manganese pentacarbonyl, greatly improves the octanenumber of the gasoline,

The following examples are illustrative of the novel gasolines,lubricating oils and antiknock fluids which are within the scope of thisinvention.

EXAMPLE I A typical method of providing fuels containing a dissolvedmanganese polycarbonyl compound is as follows: To a gasoline having afinal boiling point of 406 in a vessel provided with an agitator isadded 6.29 parts of manganese pentacarbonyl per gallon of the gasoline.After agitating the mixture for approximately fifteen minutes, themanganese carbonyl was completely dissolved and uniformly distributedthroughout the fuel. This is demonstrated by analysis of a portion ofthe fuel for manganese, which shows the fuel to contain 1.77 grams ofmanganese per gallon of fuel mixture.

EXAMPLES II-VIII Other improved gasoline compositions of this inventionprepared as in Example I are illustrated in Table V. The initial boilingpoints (IE?) and final boiling points (FBP) of the gasolines used areindicated as well as the particular manganese polycarbonyl compounds andtheir concentrations in terms of grams of manganese per gallon ofgasoline. Other such improved gasoline compositions will be apparent toone skilled in the art.

TABLE V Gasoline containing manganese polycarbonyl compounds GasolineGrams Ex. Manganese Polyearbonyl Mn Compound per IBP FBP Gal.

406 Manganese pentacarhonyl 0. 01 94 390 s -do 10.0 94 390 Aeetylmanganese pentaearbonyl- 6. 0 84 392 Ethyl manganese pentacarbonyl. 0. 189 385 Methyl manganese pentacarbonyl 2. 0 98 378 Manganesepentaearbonyl 4. 0 94 390 Propionyl manganese pentaearbonyl 1. 3

EXAMPLES 1XXIX Table VI illustrates typical gasolines of this inventionwhich contain a non-ionic manganese polycarbonyl compound in conjunctionwith an organolead compound.

The organolead antiknocks which are ingredients of certain of thecompositions of this invention are preferably hydrocarbon lead compoundssuch as tetraphenyllead, tetratolyllead and particularly tetraalkylleadcompounds such as tetramethyllead, tetraethyllead, tetrapro-Tetraethyllead is preferred. In general, the amount of organoleadantiknock agent is selected so that its content of the gasoline isequivalent to about 0.1 to-about 8 grams of lead per gallon of gasoline.v

TABLE VI Gasoline Man- Grams Scav- Example Manganese PolycarbonylAdditive ganese, Lead Antiknoek of Pb Scavenger enger Per- Gravg./gal.Agent per gal. nc., cent FBP ity, g./gal

S API IX 0 02 426 61. 4 Manganese pentacarbonyl 0. 25 Tetraethyl-lead.3. 17 {figgfiggg g ggggigg: g Y Ethylene dichloride. 1.48 X o. 02 42661.4 d0 0.1 do s. 17 {Ethylenedipmmidk 5 426 61.4 Methyl manganesepentacarbonyl 6.0 do 3.17 {ggfifiggg 390 59.0 p-OcItyl benzoyl manganesepentacarbo- 2.4 Tetramethyl-lead. 2.0 Dibromobutane 2 1 ny 366 54. 6Nonoyl manganese pentacarbonyl 4.0 Tetraphenyl-lead. 0.05 385 64.4Acetyl manganese pentacarbonyl 0. 03 Tetraethyl-1ead 8.00 {gggggg ggiggg fi 420 61.4 Benzoyl manganese pentaearhonyl 8.0 Tetrabutyl-lead-..0.1 416 63. 2 Phenyl manganese pentacarbonyl 0.,9 Tetraethyl-lead-..XVII 0.02 426 61.4 Methyl manganese pentaearbonyL; 0.05 do XVIII 420 60.8 Manganese pentacarbonyl .10

Other compositions of this invention comprising an improved gasolinecontaining a non-ionic manganese polycarbonyl compound are prepared in amanner similar to that described above and illustrated in Examples Ithrough XIX. Further, illustrative examples of the nonionic manganesepolycarbonyl compounds utilized alone or in admixture in such improvedgasolines include propionyl manganese pentacarbonyl, phenyl manganesepentacarbonyl, benzoyl manganese pentacarbonyl, trimethyl manganesetetracarbonyl, benzyl manganese pentacarbonyl, m-ethylbenz'yl manganesepentacarbonyl, and the like.

'Where halohydrocarbon compounds are employed as scavenging agents, theamounts of halogen used are given in terms of theories of halogen. Atheory of halogen is defined as the amount of halogen which is necessaryto react completely with the metal present in the antiknock mixture toconvert it to the metal dihalide, as, for example, lead dihalide andmanganese dihalide. In other words, a theory of halogen represents twoatoms of halogen for every atom of lead and/or manganese presenti Inlike manner, a theory of phosphorus is the amount of phosphorus requiredto convert the leadpres ent to lead onthophosphate, Pb '(PO that is, atheory of phosphorus based on lead represents an atom ratio of two atomsof phosphorus to three atoms of lead. When based on manganese, a theoryof phosphorus likewise represents two atoms of-phosphorus for everythree atoms of manganese, that is sufficient phosphorus to convertmanganese to manganese orthophosphate, 1

Mnsi oz- The scavenger compounds can be halohydrocarbons both aliphaticand aromatic in nature, or a combination of the two, with halogens beingattached to carbons either in the aliphatic or the aromatic portions ofthe molecule. The scavenger compounds may also be carbon, hydorgen andoxygen-containing compounds, such as haloalkyl ether, halohydrins, haloesters, halonitro compounds, and the like. Still other examples ofscavengers that may be used in conjunction with my manganese compoundseither with or without hydrocarbolead compounds are illustrated in US.Patents 2,398,281 and 2,479,900903, and the like. Mixtures of differentscavengers may also be used. These fluids can contain other componentsas stated herein above. In like manner, manganese-containing fluids areprepared containing from 0.01 to 1.5 theories of phosphorus in the formof phosphorus compounds. To make up the finished fuels, the concentratedfluids are added to the gasoline in the desired amounts and thehomogeneous fluid obtained by mixing, agitation, etc.

EXAMPLE XX To 11 parts of methyl manganese pentacarbonyl is added 5parts of ethylene dichloride and the mixture agitated until. ahomogeneous fluid results. The manganese to chlorine atom ratio in thisfluid is 1:12 and represents 6 theories of halogen based on themanganese.

In like manner, a fluid is prepared comprising benzyl manganesepentacarbonyl and ethylene dibromide in which the manganese to bromineratio is 1:6, representing 3 theories of bromine based on the manganese.Likewise, a fluid containing manganese pentacarbonyl, ethylenebromohydrin, and 2,3-dichloro-1,4-dimethylbenzene is prepared in suchproportions that for every atoms of manganese, there are one atom ofbromine and two atoms of chlorine, representing a total of 0.02 theoryof halogen.

The above fluids are added to hydrocarbon fuels in amounts so as toprovide improved fuels containing 0.015 gram, 0.25 gram, 1.00 gram, 6grams and 10 grams of manganese per gallon.

EXAMPLE XXI To 8.0 parts of lead in the form of tetraethyllead inanantiknock fluid containing 0.5 theory of bromine as ethylene dibromideand 1.0 theory of chlorine as ethylene dichloride, wherein the theoriesof halogen are based upon the amount of lead present, is added 0.015part of manganese in the form of an equimolar mixture of manganesepentacarbonyl and acetyl manganese pentacarbonyl.

This fluid is then added to a commercial hydrocarbon fuel having aninitial boiling point of 82 F. and a final boiling point of 420 F. in anamount so as to provide 8.0 grams of lead and 0.015 gram of manganeseper gallon.

EXAMPLE XXII A concentrated fluid is prepared as in Example XXcontaining kerosene, a blue dye, and 10 parts by weight of manganese asan equimolar mixture of methyl manganese pentacarbonyl and benzoylmanganese pentacarbonyl for every 0.02 part of lead in the form ofdiethyldimethyllead. This fluid is then blended with a commercialhydrocarbon fuel having an initial boiling point of F. and a finalboiling point of 394 F. in an amount suflicient to provide 10 grams ofmanganese and 0.02 gram of lead per gallon.

EXAMPLE XXIII Tetraethyllead and manganese 'pentacarbonyl are admixed sothat the ratio is 2.0 grams of lead as tetraethyllead present for every1.0 gram of manganese present as manganese carbonyl. This composition isfound to possess superior antiknock and deposit modifying propertieswhen added to gasoline.

EXAMPLE XXIV To the composition of Example XXIII is added ethylenedibromide in amount such that there is one theory of scavenger presentbased upon the total amount of metal.

The amount of the improved antiknock fluids of this invention containingorganolead compounds and manganese polycarbonyl compounds employed ingasoline is dependent primarily upon the use for which the gasoline isintended. In gasolines for use in automotive engines, such as passengercars, trucks, buses, and the like, amounts of any of the compositions ofthis invention equivalent to from between about 0.1 and about 4.3 gramsof lead per gallon are satisfactory. It will be appreciated, however,that in most cases the lead content of such improved fuels is preferablyfrom between about 1.06 and about 3.17 grams of lead per gallon which,when the organolead constituent of such fuels is tetraethyllead, isequivalent to from between about 1 and about 3 milliliters oftetraethyllead per gallon. When the improved gasolines of this inventionare designed primarily for use in aviation engines, somewhat greaterconcentrations can be tolerated and are frequently preferred. In suchinstances, it is advantageous to employ an amount of improved antiknockfluid of this invention equivalent to from between about 3.17 and about6.34 grams of lead per gallon. That is to say, when utilizing atetraethyllead-containing antiknock fluid of the present invention in anaviation fuel, amounts of such a fluid equivalent to from between about3 and about 6 milliliters of tetraethyllead per gallon are satisfactory.Concentrations above these limits can be employed in both motor andaviation fuels, practical considerations being the prime criterion forestablishingrthe upper concentration limit.

Use-of antiknock fluids containing non-ionic manganese polycarbonyls inaddition to resulting in great convenience in storage, handling,transportation, blending with fuels, and so forth, also are unexpectedlypotent concentrates which serve the multi-purpose functions of beinguseful asantiknocks, deposit modifiers, valve corrosion'inhibitors, wearreducers, and the like. The fluids are also found to. possess asurprising degree of inherent stability. I

The gasolines to which the antiknock compositions of this invention areadded are mixtures which may have a wide variation of compositions.These fuels can contain all types of hydrocarbons, including paraffins,both straight and branched chain; olefins; cycloaliphatics containingparaflin or olefin side chains; and aromatic containing aliphatic sidechains. The gasoline type depends on the base stock from which it isobtained and on the method of refining. For example, it can be astraight run or processed hydrocarbon, including thermally cracked,catalytically cracked, reformed fractions, etc. When used forspark-fired engines, the boiling range of the components of gasoline canvary from zero to about 430 F., although the boiling range of the fuelblend is often found to be between an initial boiling point of fromabout 80 F. to 100 F. and a final boiling point of about 430 F. Whilethe above is true for ordinary gasoline, the boiling range is a littlemore restricted in the case of aviation gasoline. Specifications for thelatter often call for a boiling range of from about 82 F. to about 338F., with certain fractions of the fuel boiling away at particularintermediate temperatures. All commercial gasolines including all thoseembraced within the present invention, always contain a great number ofindividual hydrocarbon compounds as components and always have a finalboiling point of at least 300 F.

The gasolines in which the antiknock agents of this invention can beemployed often contain minor quantities of various impurities. One suchimpurity is sulfur which can be present either in a combined form as anorganic or inorganic compound or as the elemental sulfur. The amounts ofsuch sulfur can vary in various fuels from about 0.003 percent to about0.30 percent by weight. Fuels containing quantities of sulfur, bothlesser and greater than the range of amounts referred to above, are alsoknown.

For best results for increasing spark plug life, the improved gasolinesof this invention should contain at least 0.015 weight percent of sulfurand preferably between 0.015 and 0.065 weight percent of this element.Spark plug life with such gasolines is spectacularly increased. Thesegasolines may also contain organolead antiknock agents in the amountsspecified above.

It will be apparent that the present invention is susceptible ofadditional variations. Some of these variants include the utilization inthe antiknock fluid embodiments of solubilizing agents, such askerosene, petroleum cuts or fractions, and in general various aromaticsolvents including those containing diphenyl and the like. In addi tionto this, various organolead stabilizers can be used in such embodiments.Among such materials are included styrene, naphthalene, lecithin,aminodiphenyl amines, phenyl-a-naphthyl amine and analogous materials.Likewise, in both the antiknock fluid and antiknock fuel embodiments ofthis invention it is frequently advantageous to employ minor proportionsof antioxidants, particularly those of the phenylene diamine type aswell as the various alkyl phenols. A still further variant within thecontemplation of this invention relates to the utilization of variousorganic dyestuffs in the antiknock fluid embodiments of this invention,which materials serve primarily as a means of product identification,although frequently the coloration produced by such dyestuffs imparts tothe composition a degree of stabilization against deteriorationresulting from exposure to light. Furthermore, under certaincircumstances benefits are to be obtained by utilizing as the scavengersin the diverse compositions of the present invention, organic halidespossessing volatilities comparable to that of the organolead antiknockagent utilized. Such scavengers are described in several of the patentscited hereinbefore.

The improved gasolines and fluids of the present invention can beutilized in conjunction with other well known motor fuel adjuvants. Ofsuch materials, the various catalytically active substances, such asphosphorus compounds comprising various phosphates, phosphites,phosphonates and the like can thus be used in various embodiments ofthis invention. Other. variants within the contemplation of thisinvention will be apparent to those skilled in the art.

The manganese polycarbonyl containing additives of this invention may bemixed with antioxidants, such as alkylated phenols and amines, metaldeactivators, phosphorus compounds; antiknock agents, such as amines aswell as the alkyllead compounds mentioned above; antirust and anti-icingagents, and wear inhibitors.

EXAMPLE XXV To 500 parts of a commercially available neutral crankcaselubricating oil is added a quantity of manganese pentacarbonylsuflicient to produce a composition containing about 2.5 weight percentmanganese. The mixture is agitated until the manganese pentacarbonyl iscompletely dispersed in the oil.

EXAMPLE XXVI To 10,000 parts of a wholly-distilled mixed base,solvent-refined lubricating oil having a gravity of 289 API, a viscositygrade of SAE 10W-20 and a viscosity index of 135.7 is added parts ofmanganese as 2,4,6- triethylbenzyl manganese pentacarbonyl and themixture is stirred until a homogeneous solution is obtained.

EXAMPLE XXVII To 1000 parts of a mixed-base, solvent-refined lubricatingoil containing bright stock and which has an SAE mixture is stirreduntil the benzoyl manganese pentacarbonyl is dissolved.

EXAMPLE XXIX H To 216 parts of a wholly distilled lubricating oil havingan API gravity of 29.1, an SAE number of lW-30 and a viscosity index of13819 is "added 3 percent of manganese as manganese pentacarbonyl. Themixture is agitated until a homogeneous solution is obtained.

The lubricating oils used in the practice of this invention includethose fractions or blends of fractions from mineral oils which are usedfor lubricating purposes in the crankcase of an internal combustionengine. Lubricating oil stock is usually considered to include all thedistillate obtainable from crude oils after the lower boiling fractionsand gas oils have been expelled, as well as some of the residues thatare left in the still when non-asphaltic crudes are distilled.

Generally lubricating oils are made from distilled fracions of a crude,but often these distilled fractions are combined with refined residuum,such as bright stocks, to yield oils having excellent lubricatingqualities.

in addition to the non-ionic manganese pentacarbonyl compound, thelubricating oils of this invention may contain ether additives. Theseother additives may include, for example, viscosity index improvers,detergents, corrosion inhibitors, metal deactivators, rust inhibitors,color stabilizers, pour depressants, emulsifiers, dyes, etc.

The non-ionic manganese polycarbonyl compounds used in the practice ofthis invention are prepared by various methods. Examples of these areindicated below.

EXAMPLE XXX pentacarbonyl, styryl manganese pentacarbonyl, and the like.

EXAMPLE XXXI Benzoyl manganese pentacarbonyl is prepared in a mannersimilar to that described in Example XXX by reacting benzoyl chloridewith sodium manganese pentacarbonyl. The benzoyl manganese pentacarbonylis gently heated to above 90 C. at which temperature a strong evolutionof gas is readily identified as carbon monoxide. When the gas evolutionceases, the remaining product is found on analysis phenyl manganesepentacarbonyl.

EXAMPLE XXXII Manganese bromide, methyl lithium, and carbon monoxide arecontacted in the presence of dioxane as a solvent at a CO pressure ofabout 5000 p.s.i.g. at 300 C. for twelve hours. A good yield oftrimethyl manganese tetracarbonyl is subsequently separated from thereaction mixture.

When the non-ionic manganese polycarbonyl compounds used in the practiceof this invention contain an organic radical, such radical has, ingeneral, from 1 to "about 20' carbon atoms. Thus, compounds -s'uital5jlefor use in the process of this invention include B ll .8 v manganesepentacarbonyl, heptaethyl manga'n" bonyl, dibutyl manganestetraca'rbonyl, methyl 'manganese pentacarbonyl, trioctyl manganesetetracarbonyl, "and the like. Theseeom'poun'ds have a molecular Weightfrom about '194 to about 50p1(manganesecarbonyl itself exists as thedimer [Mn(CO)5] andhas a'r'nolecular weight of about 390).

When the organic "group 'is a hydrocarbon radical, it preferably hasfrom l"'to'about 13 carbon atonrs'an'd the manganese polycarbonylcompound which .cont'ainsit has a molecular weight up toabout 450."Examplesjof such non-ionic manganese polycarbonyl compounds includeethyl manganese pentacarbonyl, allyl manganese pentacarbonyl, triheptylmanganese tetracarbonyl,ipentapi'bpyl 'rnanganese tricarb'onyl, "phenylmanganese'penta arbpnyl, p-hexyl benzyl manganese pentacarbonyl,andthe'like.

Likewise, when the organic group is an acyl radical or an acylatedhydrocarbon radical, it preferably contains up to about 13 carbon atomsand the non-ionic manganese polycarbonyl compound has a molecular weightup to about 465. Examples of these compounds include benzoyl manganesepentacarbonyl, tripropionyl manganese tetracarbonyl, stearoyl manganesepentacarbonyl, heptaacetyl manganese dicarbonyl, and the like.

The present invention resides in the discovery that the non-ionicmanganese polycarbonyl compounds are unexpectedly beneficial with regardto antiknock effect and deposit-modifying properties when used inconjunction with the operation of a spark ignition internal combustionengine. The invention gives rise to a number of embodiments including anovel process for operating such an engine by means of introducing anon-ionic manganese polycarbonyl compound into the combustion chambers,and a number of novel compositions which are of particular benefit insuch a process. These novel compositions include a liquid hydrocarbonmixture for use in such an engine which mixture contains a nonionicmanganese polycarbonyl compound. This liquid hydrocarbon mixture, as hasbeen pointed out, may be .a gasoline or a lubricating oil. When thehydrocarbon is a gasoline it may contain an organo-lead antiknock agentand appropriate halohydrocarbon scavengers in addition to the manganesepolycarbonyl compound. Suitable organolead compounds include the alkyllead compound, tetraethyllead, which may be present in amount such thatup to 6.34 grams or more of lead are present per gallon of fuel. Theatom ratio of manganese to lead may be from about 0.05 to 1 to 64 to 1,or, expressed differently, from about 1 to 20 to about 64 to l.Applicable halohydrocarbon scavengers include ethylene dichloride andethylene dibromide.

Further novel compositions of particular benefit in conducting theprocess of this invention comprise antiknock fluids containing anon-ionic manganese polycarbonyl. Fluids containing halohydrocarbonscavengers along with the non-ionic manganese polycarbonyl compound arealso within the scope of this invention, as are fluids containingorganolead antiknock agents in addition to the non-ionic manganesepolycarbonyl compounds. Illustrative of such fluids are those containingmanganese carbonyl and tetraethyllead such that the atom ratio ofmanganese to lead is from about 0.05 to about '64 to 1. These fluids areconveniently added to gasolines to give composition containing up to6.34 or more grams of lead per gallon.

A variant in the practice of the present invention comprises the use ofa non-ionic manganese polycarbonyl compound wherein the organic group issubstituted with a non-ionic, non-reactive group.

Having fully described the nature of the present invention, the needtherefor, and the best modes derived for carrying it out, it is intendedthat this invention be 19 limited only within the spirit and scope ofthe appended claims.

Iclaimz .1. A liquid hydrocarbon crankcase lubricating oil containin'gfrom about 0.05 to about 10.0 weight percent manganese as manganesepentacarbonyl.

I about 64:1.

"5. Gasoline containing a small antiknock quantity of manganesepentacarbonyl. V

References Cited in the file of this patent UNITED STATES PATENTS1,954,865 Danner Apr. 17, 1934 2,398,282 Bartholomew Apr. 9, 19462,434,578 Miller: Ian. 13, 1948 2,763,617 Scott et a1. Sept. 18, 1956FOREIGN PATENTS 1,092,700 France Nov. 10, 1954 OTHER REFERENCES Jour. ofthe Institute of Petroleum Technologists, vol. 13, 1927, pp. 244-255.

Jour. Amer. Chem. Soc., vol. 71, 1949, page 1899.

M a. with

1. A LIQUID HYDROCARBON CRANKCASE LUBRICATING OIL CONTAINING FROM ABOAUT0.05 TO ABOUT 10.0 WEIGHT PERCENT MANGANESE AS MANAGANESE PENTACARBOXYL.